Middle Peak Medical (MPM) is developing a novel percutaneous transcatheter technology, the MPM Mitral Leaflet Repair System, to eliminate mitral regurgitation (MR) caused by degeneration of the posterior leaflet. The System consists of the Coaptation Mesh (CM, an implant), a delivery catheter, and anchors. Given the minimally invasive route of implantation, the MPM Mitral Leaflet Repair System will be suitable for treatment of patients with moderate to severe MR who cannot or wish not be treated by surgery. Untreated MR can be debilitating, leading to poor exercise tolerance, shortness of breath, heart failure, and death. Of the 4 million U.S. patients diagnosed with MR, 600,000 fit established guidelines for operative treatment. Currently, open-heart surgery is the standard of care for these patients. Due to the significant morbidity, mortality and cost of the surgery, only about 50,000 of the sickest patients are treated annually. Nevertheless, hundreds of thousands of patients who are at high risk for open-heart surgery, or desire not to accept the morbidity and possible mortality associated with surgery, could benefit enormously from a less risky procedure. Our percutaneous approach involves placing a specially shaped synthetic mesh device, the CM, over the degenerate posterior leaflet complex using a transcatheter procedure performed by an invasive cardiologist in a cardiac cath lab. The CM, delivered through a small catheter, without surgery, will re-establish cooptation with the anterior leaflet, eliminating regurgitation. In this Phase I SBIR, we propose to provide preclinical data on the ability of the CM to reduce MR, with the following aims: Aim 1. Create an ovine model of mitral regurgitation. Our group has successfully tested this method in pilot studies. MR will be monitored using ventriculography, echocardiography, and hemodynamic measurements and a standard grading scale (0,1-4+). Milestone: create MR of at least 3+ in the setting of flail posterior leaflet cause by severing a chord to the leaflet edge. Aim 2. Demonstrate reduction of mitral regurgitation after surgical attachment of the CM. Following suture anchoring of the CM, we will monitor MR using ventriculography, echocardiography and hemodynamics. Reduction of MR will be measured immediately after CM implantation and one month post-op. Milestones: MR reduced to <2+ immediately post-op and MR <2+ maintained one month post implant, without damage to other parts of the heart or significant transmitral inflow pressure gradient. At the successful completion of this Phase I SBIR, we will be poised to begin a two-year Phase II SBIR, during which we will a) finalize the CM implant design; b) refine our percutaneous catheter delivery and anchoring system (developed using separate financing) to harmonize with the ultimate CM design; and c) perform such longer term chronic testing and in vitro studies as required to initiate an FDA-approvable Investigational Device Exemption (IDE) clinical trial. Our long- term goal is approval by the FDA for commercial sale within the US via the Premarket Approval process.